Harper caught 52 passes for 634 yards and six touchdowns in 12 games in 2014. He also contributed on special teams, amassing 100 yards on 13 punt returns.
Over three seasons, the 5-foot-11, 175-pound Harper recorded 159 catches for 1,969 yards and 14 touchdowns.
Here is part of a statement released by Harper:
"After having many talks with my family, mentors and coaches I have decided that declaring for the NFL Draft was best for me at this time," Harper said. "Millions of different thoughts and prayers have been put into this educated decision which is why I have decided to enter the draft."
On Tuesday, Bryce Treggs, one of Cal's other top receivers, indicated in a message posted to his Twitter account that he will return for his senior season. "I'm committed to the guys that strap up and go to war with me on Saturdays," Treggs wrote. "I can't wait to ball out with them for my last college season."
Cal lost six of its final seven games and finished 5-7 this season.